Magnus and his crew aboard the Kinloch Bravo oil rig are stationed off the Scottish coast in the dangerous waters of the North Sea. When they are due to be collected and return to the mainland a mysterious and all-enveloping fog rolls through. The rig is hit by massive tremors, and they find themselves cut off from all communication with the shore and the outside world. As the crew endeavour to discover what's driving this unknown force, a major accident forces them to ask questions about who they can really trust. Bonds are broken, allegiances formed and generational fault lines exposed. The crew of the Bravo will be driven to the limits of both their loyalties and their endurance, into a confrontation with forces beyond their imagination.